Head driving circuit

Abstract

The invention comprises a voice coil motor for moving a head for reading information from or writing information to a disk, a driving circuit for supplying current to the voice coil motor in response to a first control signal and for changing the gain of the driving circuit in response to a second control signal. The gain of the driving circuit is increased during a moving control mode (i.e. a seek mode) and decreased during a position control mode (i.e. a track-following mode).

What is claimed is: 
     
       1. A head driving apparatus in a data storage apparatus, the data storage apparatus including a recording medium and a head disposed adjacent to the recording medium, comprising: a voice coil motor for moving the head to a plurality of predetermined positions adjacent to the recording medium,   driving means for supplying an exciting current to said voice coil motor in response to a drive signal and a gain selection signal,   gain control means for producing said gain selection signal, said gain selection signal corresponding to a high gain in a seek mode and corresponding to a low gain in a track-following mode.   
     
     
       2. The head driving apparatus according to claim 1, wherein said driving means comprises: an operation amplifier having a first terminal for receiving said drive signal and a second terminal for receiving a reference voltage and an output;   a plurality of resistors for determining the gain of said operation amplifier, and   a transistor including a base connected to the output of said operation amplifier, a collector connected to said voice coil motor, and an emitter connected to at least one of said plurality of resistors.   
     
     
       3. The head driving apparatus according to claim 1, wherein said recording medium comprises a magnetic disk. 
     
     
       4. The head driving apparatus according to claim 1, wherein said recording medium comprises an optical disk. 
     
     
       5. The head driving apparatus of claim 1, wherein said gain control means comprises a control unit and a digital-to-analog converter. 
     
     
       6. The head driving apparatus of claim 1, further comprising a speed sensing system for sensing the speed of the head connected to the gain control means and a position sensing system for sensing the position of the head connected to the gain control means. 
     
     
       7. The head driving apparatus of claim 2, wherein said driving means further comprises: a second operational amplifier having a first terminal for receiving said drive signal and a second terminal for receiving a reference voltage and an output;   a plurality of resistors for determining the gain of said operation amplifier, and   a transistor including a base connected to the output of said operation amplifier, a collector connected to said voice coil motor, and an emitter connected to at least one of said plurality of decreased during a position control mode (i.e. a track-following mode).